Vivo treatment of skin lesions by electrical nanopulses

ABSTRACT

This disclosure relates to an in vivo treatment of a skin lesion of a mammal comprising application of electrical energy to the skin lesion in a form of electrical pulses. At least one electrical pulse is applied. The pulse duration may be at least 0.01 nanoseconds at the full-width-at-half-maximum. This treatment may at least prevent growth of the lesion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of prior application Ser. No. 13/631,618, filed Sep. 28, 2012, which is a continuation-in-part of prior application Ser. No. 13/565,630, filed Aug. 2, 2012, entitled “In Vivo Treatment of Skin Lesions by Electrical Nanopulses,” which is based upon and claims priority to U.S. Provisional Application No. 61/514,733, filed Aug. 3, 2011. The entire contents of these applications are incorporated herein by reference.

BACKGROUND Technical Field

This disclosure relates to in vivo treatment of skin lesions of mammals and to application of electrical pulses with a duration of 1,000 nanoseconds or less.

Description of Related Art

Ultra-short, high-field strength electric pulses may be used in the electroperturbation of biological cells. For example, these electric pulses may be used in treatment of human cells and tissue including tumor cells, such as basal cell carcinoma, squamous cell carcinoma, and melanoma. For a detailed discussion of such applications, for example, see, Garon et al. “In Vitro and In Vivo Evaluation and a Case Report of Intense Nanosecond Pulsed Electric Field as a Local Therapy for Human Malignancies”, Int. J. Cancer, vol. 121, 2007, pages 675-682. The entire content of this publication is incorporated herein by reference.

The voltage induced across a cell membrane may depend on the pulse length and pulse amplitude. Pulses longer than about 1 microsecond may charge the outer cell membrane and lead to opening of pores, either temporarily or permanently. Permanent openings may result in cell death.

Pulses shorter than about 1 microsecond may affect the cell interior without adversely or permanently affecting the outer cell membrane. Such shorter pulses with a field strength varying in the range of 10 kV/cm to 100 kV/cm may trigger apoptosis (i.e. programmed cell death). These higher electric field strengths and shorter electric pulses may be useful in manipulating intracellular structures, such as nuclei and mitochondria.

Nanosecond high voltage pulse generators have been proposed for biological and medical applications. For example, see: Gundersen et al. “Nanosecond Pulse Generator Using a Fast Recovery Diode”, IEEE 26.sup.th Power Modulator Conference, 2004, pages 603-606; Tang et al. “Solid-State High Voltage Nanosecond Pulse Generator,” IEEE Pulsed Power Conference, 2005, pages 1199-1202; Tang et al. “Diode Opening Switch Based Nanosecond High Voltage Pulse Generators for Biological and Medical Applications”, IEEE Transactions on Dielectrics and Electrical Insulation, Vol. 14, No. 4, 2007, pages 878-883; Yampolsky et al., “Repetitive Power Pulse Generator With Fast Rising Pulse” U.S. Pat. No. 6,831,377; Schoenbach et al. “Method and Apparatus for Intracellular Electro-Manipulation”, U.S. Pat. No. 6,326,177; Gundersen et al., “Method for Intracellular Modifications Within Living Cells Using Pulsed Electric Fields”, U.S. Patent Application No. 2006/0062074; Kuthi et al., “High Voltage Nanosecond Pulse Generator Using Fast Recovery Diodes for Cell Electro-Manipulation”, U.S. Pat. No. 7,767,433; Krishnaswamy et al., “Compact Subnanosecond High Voltage Pulse Generation System for Cell Electro-Manipulation”, U.S. Patent Application No. 2008/0231337; and Sanders et al. “Nanosecond Pulse Generator”, U.S. Patent Application No. 2010/0038971. The entire content of these publications is incorporated herein by reference.

SUMMARY

This disclosure relates to an in vivo treatment of a skin lesion of a mammal comprising application of electrical energy to the skin lesion in the form of one or more electrical pulses. The pulse duration may be at least 0.01 nanoseconds (ns) at the full-width-half-maximum (FWHM). The pulse duration may also be at least 1 ns at FWHM. Or the pulse duration may be at least 5 ns at FWHM. The pulse duration may be 1,000 ns or shorter at FWHM. This treatment may at least prevent growth of the lesion.

The phrase skin lesion, as used herein, is any deviation of skin from a healthy or a normal condition. Examples of skin lesions are skin diseases, conditions, injuries, defects, abnormalities or combinations thereof. For example, such skin lesions include malignancies (such as basal cell carcinomas, squamous cell carcinomas and melanoma), precancerous lesions (such as actinic keratosis), human papilloma virus (HPV) infected cells (such as verruca vulgaris or common warts, plantar warts, genital warts), immune-related conditions (such as psoriasis), other skin abnormalities (such as seborrheic keratosis and acrocordon), or combinations thereof. In one embodiment, the skin lesion is basal cell carcinoma (including papilloma), squamous cell carcinoma, actinic keratosis, warts, or combinations thereof. The skin lesion may also include aged skin, wrinkled skin or damaged skin. An example of the damaged skin is the skin damaged by sun radiation.

This treatment may at least prevent growth of the skin lesion for a duration of one week after the treatment. This treatment may reduce the skin lesion volume by at least 50% within one week after the treatment. This treatment may clear the lesion within one week after the treatment for at least 50% of cases.

The duration of the pulse at FWHM may be in the range of 0.01 ns to 1,000 ns. The duration of the pulse at FWHM may also be in the range of 1 ns to 100 ns, or in the range of 1 ns to 30 ns.

The applied electrical energy per volume of the skin lesion may be at least 10 mJ/mm³ or at least 100 mJ/mm³ or at least 1,000 mJ/mm³. The applied electrical energy per volume of the skin lesion may also be in the range of 10 mJ/mm³ to 10,000 mJ/mm³.

The electrical field produced by each pulse may be at least 1 kV/cm at the peak amplitude of the pulse. The electrical field produced by each pulse may also be at least 10 kV/cm at the peak amplitude of the pulse. The electrical field produced by each pulse may be in the range of 1 kV/cm to 1,000 kV/cm at the peak amplitude of the pulse. The electrical field produced by each pulse may be in the range of 10 kV/cm to 100 kV/cm at the peak amplitude of the pulse.

The number of electrical pulses during a single treatment may be at least 10. The number of pulses may also be at least 100. Yet, the number of pulses may be at least 1,000. The number of pulses may be less than 10,000.

In one embodiment, this treatment may be an in vivo treatment of a skin lesion of a human comprising at least one treatment session, i.e. administration of the electrical energy to the skin lesion by physician at an office visit. The at least one treatment session may comprise applying electrical energy to the skin lesion of the human comprising delivering at least one electrical pulse with a pulse duration at FWHM in the range of 0.01 ns to 1,000 ns, forming an electrical field in the lesion, and thereby at least preventing growth of the lesion. This pulse duration at FWHM may also be in the range of 1 ns to 100 ns, or in the range of 1 ns to 30 ns.

In this embodiment, the skin lesion of a human may be any deviation of skin from a healthy condition. The skin lesion may also be malignancies, precancerous lesions, human papilloma virus (HPV) infected cells, immune-related conditions, seborrheic keratosis, acrocordon, or combinations thereof. The skin lesion may also include aged skin, wrinkled skin or damaged skin. An example of the damaged skin is the skin damaged by sun radiation. The skin lesion may be basal cell carcinoma, squamous cell carcinoma, actinic keratosis, warts, or combinations thereof. The skin lesion may be common warts, actinic keratosis or combinations thereof. The skin lesion may be actinic keratosis.

In this embodiment, the pulse duration at FWHM may be in the range of 0.01 ns to 1,000 ns; or in the range of 1 ns to 100 ns, or in the range of 1 ns to 30 ns. The electrical field formed by each pulse at the peak amplitude of the pulse may be at least 1 kV/cm; at least 10 kV/cm; in the range of 1 kV/cm to 1,000 kV/cm; or in the range of 10 kV/cm to 100 kV/cm. Applying electrical energy may comprise applying at least 10 pulses during a treatment, at least 100 pulses, or at least 1,000 pulses. The applied electrical energy per volume of the skin lesion may be at least 10 mJ/mm³, at least 100 mJ/mm³, at least 1,000 mJ/mm³, or in the range of 10 mJ/mm³ to 10,000 mJ/mm³.

In one embodiment, the skin lesion of the human may be common warts. In this embodiment, the applied electrical energy per volume of the skin lesion may be at least 920 mJ/mm³ to at least prevent growth of the warts. The wart treatment may induce at least 21% shrinkage of the wart, or at least 40% shrinkage of the wart, or at least 70% shrinkage of the wart. Common warts may also be cleared by this treatment. This treatment may at least prevent the growth of the warts. And the at least prevention of the wart growth may last at least 41 days.

In another embodiment, the skin lesion of the human may be actinic keratosis. For this treatment, the applied electrical energy per volume of the skin lesion may be at least 473 mJ/mm³ to at least prevent growth of the actinic keratoses. This treatment may be carried out to induce at least 20% shrinkage of the actinic keratosis, or at least 40% shrinkage of the actinic keratosis, or at least 70% shrinkage of the actinic keratosis. This treatment may also be carried out to clear actinic keratoses. This treatment may at least prevent growth of the actinic keratoses. And the at least prevention of the actinic keratosis growth may last at least 56 days.

The treatment of a human lesion may also comprise a plurality of treatment sessions. For example, it may comprise at least two treatment sessions or at least three treatment sessions.

The system used for the treatment of the skin lesion may include an applicator tip that comprises at least one delivery electrode and at least one ground electrode.

These, as well as other components, steps, features, objects, benefits, and advantages, will now become clear from a review of the following detailed description of illustrative embodiments, the accompanying drawings, and the claims.

BRIEF DESCRIPTION OF DRAWINGS

The drawings disclose illustrative embodiments. They do not set forth all embodiments. Other embodiments may be used in addition or instead. Details which may be apparent or unnecessary may be omitted to save space or for more effective illustration. Conversely, some embodiments may be practiced without all of the details which are disclosed. When the same numeral appears in different drawings, it refers to the same or like components or steps.

FIG. 1: Example of a system for generation and delivering electrical nanopulses to a skin lesion.

FIG. 2: Example of a simplified diode pulse generator.

FIG. 3: Example of an electrical pulse generated by the system shown in FIG. 1.

FIG. 4: Example of an applicator tip with one delivery electrode and four ground electrodes.

FIG. 5: Photograph of lesions on a mouse before a treatment.

FIG. 6: Photograph of lesions on the mouse shown in FIG. 5 one week after the treatment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Illustrative embodiments are now discussed. Other embodiments may be used in addition or instead. Details which may be apparent or unnecessary may be omitted to save space or for a more effective presentation. Conversely, some embodiments may be practiced without all of the details which are disclosed.

This disclosure relates to an in vivo treatment of skin lesions of mammals by application of electrical pulses with duration of 1,000 nanoseconds (ns) or less as measured at the full-width-at-half-maximum (FWHM) of the pulse wave.

The skin lesion that may be treated in vivo by the devices described herein may be any deviation of skin from a healthy or a normal condition. Examples of the skin lesions include skin diseases, conditions, injuries, defects, abnormalities or combinations of thereof. For example, such skin lesions may be malignancies (such as basal cell carcinomas, squamous cell carcinoma and melanoma), precancerous lesions (such as actinic keratosis), human papilloma virus (HPV) infected cells (such as verruca vulgaris or common warts, plantar warts, genital warts), immune-related conditions (such as psoriasis), other skin abnormalities (such as seborrheic keratosis and acrocordon) and combinations thereof. The skin lesion may also include aged skin, wrinkled skin or damaged skin. An example of the damaged skin is the skin damaged by sun radiation. In one embodiment, the skin lesions may be basal cell carcinoma (including papilloma), squamous cell carcinoma, actinic keratosis, warts, or combinations thereof. In one embodiment, the skin lesion may be a skin lesion of a human. In this embodiment, the skin lesion may comprise basal cell carcinoma, squamous cell carcinoma, actinic keratosis, warts, or combinations thereof. In this embodiment, the skin lesion may also comprise common warts, actinic keratosis, or combinations thereof. The skin lesion may be a common wart of a human. The skin lesion may also be an actinic keratosis of a human.

The in vivo treatment may be achieved by providing electrical energy to the skin lesion in a form of one or more electrical pulses. During this treatment, tissue removal may not be intentional and, if it happens, may not be substantial. Thus, the treatment may thereby be advantageous over current or other proposed treatment techniques, since it may achieve its purpose with no substantial tissue removal.

The in vivo treatment of the skin lesion may at least prevent growth of the lesion. In one embodiment, the treatment may reduce the volume of the skin lesion. That is, the treatment induces at least shrinkage of the lesion. This shrinkage may be at least 10%, 20%, 30%, 60%, 70%, 80%, 90%, or more than 90%. Yet, in another embodiment, it may be a treatment to reduce the skin lesion volume to a negligible level (i.e. clearance of the lesion). Yet, in other embodiments, the lesion growth prevention or the lesion volume reduction may be achieved in at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or more than 90% of cases.

When the lesion volume shrinks to a negligible size (i.e. about 100%), the lesion is “cleared”. If the lesion growth or shrinkage is less than 10% after the treatment, the lesion growth is considered to have been “prevented” or that there is “no change”. If the lesion shrinkage is in the range of >10% and <50%, it is concluded that there is lesion “shrinkage”. If the lesion shrinkage is in the range of >50% and <100%, it is concluded that there is “substantial shrinkage”. If the lesion growth is in the range of >10% to <100%, it is concluded that there is lesion “growth”. And if the lesion growth is >100%, it is concluded that there is “substantial growth”.

If the height (i.e. protrusion) of the lesion above the skin surface is negligibly small, i.e. about 0.00 mm, the lesion height is recorded as about 0.10 mm.

The treatment results may be permanent or temporary. In one embodiment, the growth prevention, or the shrinkage or the clearance may last for a duration of at least 7 days, at least 10 days, at least 20 days, at least 30 days, at least 40 days, at least 50 days, at least 60 days, at least 70 days, at least 80 days, at least 90 days, at least 100 days, or at least 110 days.

In one embodiment, the treatment comprises at least one treatment session. For example, the treatment session may comprise an administration of the electrical energy to the skin lesion of a human by physician at an office visit. The treatment of a human lesion may also comprise a plurality of treatments sessions. For example, it may comprise at least two treatment sessions or at least three treatment sessions.

Furthermore, these electrical nanopulse treatments may be combined with any other treatment to increase efficacy of the lesion treatment. These other treatments may include over-the-counter treatments, treatments with prescription medicines, surgery, and destructive procedures. For example, these other lesion treatments may include curettage, electrodessication, cryotherapy, topical therapy, and combinations thereof.

Any system suitable for delivery of electrical nanopulses with a duration of 1,000 ns or less at FWHM to the skin lesion may be used.

The system may comprise a power supply, a controller, a pulse generator, and a pulse delivery device (e.g., a wand). An example of this system is schematically shown in FIG. 1.

The pulse generator may be any pulse generator that is capable of generating pulses with a duration of 1,000 ns or less at FWHM. Examples of such pulse generators are disclosed in Kuthi et al., “High Voltage Nanosecond Pulse Generator Using Fast Recovery Diodes for Cell Electro-Manipulation”, U.S. Pat. No. 7,767,433; Sanders et al. “Nanosecond Pulse Generator”, U.S. Patent Application No. 2010/0038971; and Schoenbach et al. “Method and Apparatus for Intracellular Electro-Manipulation”, U.S. Pat. No. 6,326,177. The content of these publications are incorporated herein by reference.

The pulse delivery device may be any device that can deliver electrical pulses to the skin lesion. This device may have an applicator tip that may comprise at least one delivery electrode. This applicator may further comprise at least one ground electrode. In one embodiment, the delivery electrode and/or the ground electrode may penetrate into the skin lesion to deliver the electrical pulses. In another embodiment, the delivery electrode and/or the ground electrode may deliver the electrical pulses without substantially or intentionally penetrating into the skin lesion. For example, the skin lesion may be constricted between the electrodes or the electrodes may only touch the lesion during the delivery of the electrical pulses.

An example of the applicator tip is illustrated in FIG. 4. In this example, the applicator tip has one delivery electrode placed at the center and four ground electrodes surrounding the delivery electrode. The base of the electrodes may be embedded in a solid insulating material to maintain separations between them.

The electrical energy may be applied to the skin lesion in the form of at least one electrical pulse. In one embodiment, at least 10 pulses, at least 100 pulses or at least 1,000 pulses may be applied to treat the lesion during a single treatment.

In one embodiment, the duration of one or more of the pulses at FWHM may be in the range of 0.01 ns to 1,000 ns. The duration of one or more of the pulses at FWHM may also be in the range of 1 ns to 100 ns or in the range of 1 ns to 30 ns.

Total electrical energy applied per volume of skin lesion may be at least 10 mJ/mm³, at least 20 mJ/mm³, at least 100 mJ/mm³, at least 500 mJ/mm³, or at least 1,000 mJ/mm³. In another embodiment, the total applied electrical energy per volume of the skin lesion may be in the range of 10 mJ/mm³ to 10,000 mJ/mm³.

The electrical field produced by each pulse may be at least 1 kV/cm at the peak amplitude of the pulse. The electrical field produced by each pulse may also be at least 10 kV/cm at the peak amplitude of the pulse. In another embodiment, the electrical field produced by each pulse may be in the range of 1 kV/cm to 1,000 kV/cm at the peak amplitude of the pulse. Yet, in another embodiment, the electrical field produced by each pulse may be in the range of 10 kV/cm to 100 kV/cm at the peak amplitude of the pulse.

The treatment may comprise at least one treatment session, i.e. administration of the electrical energy to the skin lesion by physician at an office visit. This treatment session may comprise at least one application of the electric energy to a lesion. The electrical energy may be delivered to the skin lesion in any manner suitable for the skin lesion. For example, the electrical energy may be delivered after contacting the surface of the lesion by electrodes of the applicator tip. In this example, the electrodes don't penetrate into the lesion during the application of the electrical energy. In another example, the electric energy may also be delivered after insertion of the electrodes to the skin lesion. For example, one application may comprise first penetration of the skin lesion by the electrodes of the applicator tip and then delivery of about 100 pulses with a pulse duration of about 18 ns at FWHM. More than one application may be used per treatment session to treat the lesion. The number of applications may depend on the size and/or the type of the lesion. Larger lesions may require more than one application per treatment session, as discussed in detail below. Also, different types of lesions may require higher energies, and therefore more applications per treatment session may be needed to at least prevent the growth of the lesions. The treatment of a lesion may also comprise a plurality of treatment sessions. For example, it may comprise at least two treatment sessions or at least three treatment sessions. These treatment sessions may also be separated in time by 7 days or more.

Example 1. Nanopulse Generator and Electrical Nanopulses

An electrical pulse generation and delivery system, schematically shown in FIG. 1, comprising a pulse generator was constructed at the Alfred E. Mann Institute for Biomedical Engineering at the University of Southern California (Los Angeles, Calif.).

An example of the pulse generator is schematically shown in FIG. 2. This pulse generator was previously disclosed in detail in U.S. Pat. No. 7,767,433 to Kuthi et al. and in U.S. Patent Application U.S. 2010/0038971 to Sanders, the content of which is incorporated by reference. This pulse generator is briefly described below:

As shown in FIG. 2, the diode pulse generator may include a tank circuit consisting of inductances L₁ and L₂ and capacitances C₁ and C₂. The tank circuit may be connected in series with a diode D across which a load R_(L) to be driven may be connected. This load may be the resistance of the lesion or tissue. The pulse generator may include a switching system, such as switches S₁ and S₂, which may be electronic. A voltage supply V_(in) may be connected to the diode pulse generator through a resistance R_(ch).

Before the beginning of a pulse cycle, the switch S₁ may be open and the switch S₂ may be closed. This may cause the capacitance C₁ to fully charge and the capacitance C₂ to fully discharge.

At the beginning of the pulse cycle, the switch S₁ may be closed and the switch S₂ may be opened. This may cause charge to transfer from the capacitance C₁ to the capacitance C₂. During this transfer, the current through the tank circuit may rise and fall in approximately a sinusoidal manner.

This current may cause the diode D to be forward-biased as it travels travel through it. During this process, charge may be stored in the depletion layer of the diode D.

At the end of the half-cycle, switch S₂ may be closed. During the next half-cycle, the current flow may reverse in direction, causing the diode D to be reverse-biased. During the first part of the second half-cycle, current may still flow through the diode D while charge in its depletion layer is being depleted. Once the charge is depleted, the current through the diode D stops, causing the diode to appear as an open switch. This may cause the current through the inductance L₂ to commute from the diode D to the load R_(L). The diode D may thus be configured to act as an opening switch, interrupting the current in the inductance L₂ and commuting it into the load R_(L).

Current may now travel through the load R_(L) until the energy stored in the tank circuit consisting of the capacitance C₂ and the inductance L₂ depletes, thus delivering a pulse into the load R_(L).

This pulse generator included a current limiting resistor, R_(CL) configured to limit damage to the pulse generator. The value of this resistor was about 1 ohm. The pulse generator further included a terminating resistance, R_(T) in parallel with the diode, wherein the terminating resistance was configured to protect the output stage of the pulse generator. The value of this resistor was about 100 ohms.

The pulse generator disclosed above provided at least one electrical pulse with a duration varying in the range of about 7 nanoseconds (ns) at FWHM to about 20 ns at FWHM. In one example, a pulse with duration of about 20 ns at FWHM was generated. The characteristics of this pulse were recorded by an oscilloscope manufactured by Tektronix (Beaverton, Oreg.) with a model number of DP04104. As shown in FIG. 3, this pulse had pulse duration of about 20 ns at FWHM and a peak amplitude of about 8.00 kV.

The electrical nanopulses were delivered to a lesion by using applicator tips comprising one delivery electrode and four ground electrodes surrounding the delivery electrode. This applicator tip is shown in FIG. 4. Each electrode was constructed by using a 30 gauge needle (i.e. about 0.255 mm in diameter). The delivery and the ground electrodes have the same the length for each applicator tip. This length varied in the range of about 2 millimeters (mm) to 5 mm. The electrodes were placed to form a square pattern. The ground electrodes were at the corners of this square and the delivery electrode was at its center. Center-to-center distance between the delivery electrode and each ground electrode was about 1.75 mm. This configuration provided a volume of about 30.625 cubic-millimeters (mm³) within the boundary formed by ground electrodes. The ground electrodes and the delivery electrode were electrically isolated from each other by embedding them in a Teflon insulation (not shown in FIG. 4).

The tip configuration may be different than illustrated. There may be other applicator tip configurations suitable for the treatment of the lesions. These configurations may include tips comprising at least one delivery electrode and at least one ground electrode. For example, as the system disclosed above is coaxial in nature, with the ground electrodes surrounding the delivery electrode, any number of needle configurations may be realized, including a circular arrangement with five or more ground electrodes, a triangular arrangement with three ground electrodes, wherein the delivery electrode may be placed at the geometrical center of such arrangements. A simple linear arrangement with just two opposing electrodes, i.e., one return electrode and one delivery electrode, may also be used for the delivery of the electrical pulses.

Still other tip configurations, for example those with different electrode spacing or length, may also be used for the treatment of the lesions. However, as the effect of these short pulses on cells is largely dependent upon the strength of electric field, an increase in return and active electrode spacing may have to be accompanied by a proportional increase in output voltage to maintain the required field for the effect on cells. Similarly, if the spacing is reduced, the voltage could be proportionally decreased.

Each pulse with a duration of about 7 ns at FWHM contained significant frequency components centered at about 142.9 megahertz (MHz), and each pulse with a duration of about 14 ns at FHWM contained significant frequency components centered at about 71.4 MHz. Electrical nanopulses with two different amplitudes, one with a peak amplitude of about 7.0 kilovolts (kV) and other with a peak amplitude of about 5.5 kV, were generated with a frequency of about 50 pulses per second. The electrical field was about 40 kilovolts/centimeter (kV/cm) at the peak amplitude of about 7.0 kV and about 31 kV/cm at the peak amplitude of about 5.5 kV.

Values of the pulse durations and the peak amplitudes disclosed in this document were average values unless specifically noted. These pulse durations and the peak amplitudes may vary with a standard deviation of 10% of their average values. For example, the pulse duration of about 7 ns at FWHM may be an average of pulse durations that vary within the range of 6.30 ns and 7.70 ns, or it is 7.00±0.70 ns. Similarly, the peak amplitude of about 7.00 kV may be an average of the peak amplitudes that vary within the range of 6.30 kV and 7.70 KV, or it is 7.00±0.70 kV.

Electrical power delivered by the applicator tip at the peak of the pulse, P_(peak) is:

P _(peak) =V ² _(peak) /R _(L)  Equation 1

where, V_(peak) is peak amplitude of electrical potential. R_(L) was fixed at about 100 ohms when the pulse generator was configured. That is, the lesion resistance was expected to be about 100 ohms.

And, the electrical energy delivered by the applicator tip per pulse, E_(p) is:

E _(p)=(2×P _(peak) ×t _(FWHM))/3  Equation 2

where, t_(FWHM) is the pulse duration at FWHM.

Then, for R_(L) of about 100 ohms and V_(peak) of about 7.00 kV, the total energy delivered to the tissue per pulse was calculated to be about 2.29 millijoules (mJ) for the pulse duration of about 7 ns at FWHM, about 4.57 mJ for the pulse duration of about 14 ns at FWHM, or about 5.88 mJ for the pulse duration of about 18 ns at FWHM. For R_(L) of about 100 ohms and V_(peak) of about 5.5 kV, the total energy delivered to the tissue per pulse was calculated to be about 2.82 mJ for the pulse duration of about 14 ns at FWHM

Example 2. Mouse Model and Formation of Skin Lesions

All experiments with mice were conducted after experimental procedures were approved by Institutional Animal Care and Use Committee (IACUC) of Department of Comparative Medicine Cedars Sinai Medical Center, Santa Monica, Calif. For all procedures, mice were given isofluorane anesthesia and positioned on a warming bed.

Cutaneous papillomas and squamous carcinomas were chemically induced according to an established protocol disclosed in following publications: Hennings H, Shores R, Mitchell P, Spangler E F, Yuspa S H “Induction of papillomas with a high probability of conversion to malignancy” Carcinogenesis (1985) 6:1607-10; Hennings H, Spangler E F, Shores R, Mitchell P, Devor D, Shamsuddin A K, Elgjo K M, Yuspa S H “Malignant conversion and metastasis of mouse skin tumors: a comparison of SENCAR and CD-1 mice” Environmental health perspectives (1986) 68:69-74; and Slaga T J “SENCAR mouse skin tumorigenesis model versus other strains and stocks of mice” Environmental health perspectives (1986) 68:27-32. The entire content of these publications is incorporated herein by reference.

SENCAR (SENsitivity to CARcinogenesis) and CD-1 mice were used as model animals to induce tumors on their skin and to treat these tumors with electrical nanopulses. SENCAR mice were developed from CD-1 mice by recurrent selection of mice that are sensitive to chemically induced tumor development. SENCAR-A mice (SENCAR A/PtCr) were provided by National Cancer Institute, Frederick, Md. and SENCAR-C mice (SENCAR C/PtJ) were purchased from The Jackson Laboratory, Bar Harbor, Me. CD-1 mice were bought from Charles River Laboratories International Inc., Wilmington, Md. Both SENCAR and CD-1 mice were maintained in Cedars Sinai Medical Center's animal facility.

Carcinogen was applied on the flank of the shaven murine skin using a cotton-tipped applicator. Briefly, tumors were initiated using about two micromoles of methyl-N′-nitro-N-nitrosoguanidine (MNNG) on the first week followed by promotion of the tumor using about two micrograms of 12-O-tetradecanoylphorbol-13-acetate (TPA) which was applied weekly. After 16 to 30 weeks, two to eight tumors (papillomas or carcinomas) were visually detected on each mouse, characterized by rapid growth with elevated margins. These tumors were pink in color and bulbous in appearance.

Based on histology, size and appearance of lesions (i.e. tumors), about 30% of them were expected to be squamous cell carcinomas showing signs of invasiveness and about 70% were expected to be papillomas. The papillomas are similar to human hypertrophic actinic keratosis (AK). AK is earliest identifiable lesion that may eventually develop into an invasive squamous cell carcinoma (SCC). AK is also clinically quite common and diagnosed in about 14% of all visits to dermatologists. Tumor growth was monitored by measuring size of each tumor using a caliper. Morphology of induced tumors was periodically examined using standard histology.

Examples 3 to 59. Application of Nanosecond Electrical Pulses to Skin Lesions

In Examples 3 to 59, the tumors, which were formed on the mice skin by following the method in the manner of Example 2, were treated by using the nanopulse generator and the applicator tip disclosed in Example 1.

To avoid formation of air pockets between the electrodes, both the tumor and the electrodes were covered with Aquasonic 100 ultrasound transmission gel (Parker Laboratories Inc., Fairfield, N.J., USA). Electrical pulses with varying duration, amplitude and number were delivered to the skin lesion to determine effects of these pulse parameters on tumor treatment.

Photographs of tumors were taken before and after each treatment and also one week after the treatment to record shape of the tumor, as shown in FIG. 5 and FIG. 6 by way of example.

Tumor size was measured before each treatment and one week after the treatment by using a vernier caliper. The highest elevation of the tumor as measured from the healthy skin surface was recorded as the tumor height. The longest length of the tumor as measured parallel to the healthy skin surface was recorded as the tumor length. For example, before the treatment, the size of the tumors shown in FIG. 5 were about 5.5 mm (length)×about 4 mm (width)×about 3 mm (height) in Example 36 and about 2.5 mm (length)×2.50 mm (width)×2.00 mm (height) in Example 3.

The widest size perpendicular to the tumor length was recorded as the tumor width. The tumor volume, T_(V) was then calculated by using the following equation:

T _(V)=0.625×T _(L) ×T _(W) ×T _(H)  Equation 3

where T_(L) is the tumor length, T_(W) is the tumor width and T_(H) is the tumor height. The percent of tumor growth or shrinkage T_(C) is:

T _(C)=100×(T _(V,after) −T _(V,before))/T _(V,before)  Equation 4

where T_(V,after) is the tumor volume measured one week after the treatment and T_(V,before) is the tumor volume measured before the treatment.

For example, the volumes of the tumors shown in FIG. 5 were about 7.81 mm³ in Example 3 and about 41.25 mm³ in Example 36. As shown in FIG. 6 and summarized in Table 1, one week after the treatment, the tumor in Example 3 grew in volume by about 170%, as expected since this tumor was penetrated with the applicator tip but no electrical energy was applied to the tumor. And the tumor in Example 36 was cleared, i.e. its volume reduced by about 100%.

The pulse duration at FWHM, the pulse amplitude, and the number of pulses per application were set on the pulse generator. Then, the tumor was slightly elevated from the skin surface by inserting fingers gently under the tumor. Finally, the electrodes were vertically inserted into the tumor and the electrical pulses were applied. Great care was taken to prevent the electrodes from penetrating beyond the height of the tumor. Thus, during the application of the electrical pulses, the electrodes' distal ends were guided so that the electrodes did not penetrate deeper than the measured height of the tumor. For example, if the measured tumor height was about 3.00 mm, the penetration depth was also about 3.00 mm.

Surface of the tumors, facing the applicator tip, was generally round, but sometimes elliptical or elongated in shape. Locations for insertion of the delivery electrode were visually decided and evenly distributed on this surface. One application was carried out for each millimeter of the tumor length. Tumors shorter than one millimeter in length were not treated. For the tumors, which were longer than one millimeter but had lengths that were in fractions of a millimeter where the fractional length was in the range of 0.5 mm to 1.0 mm, the tumor length was rounded up to calculate the number of applications. For example, for the tumors that had lengths about 5.5 mm, 6 applications were carried out.

The center-to-center distance between two opposing ground electrodes was about 3.50 mm. For some tumors, this distance was wider than the width of these tumors. For these tumors, the ground electrodes partially penetrated into the tissue surrounding the tumor.

The total electrical energy delivered by the applicator tip per treatment, E_(T) is:

E _(T) =E _(P) ×N _(P) ×A _(N)  Equation 5

where N_(P) is the number of pulses per application and A_(N) is number of applications per tumor. Electrical energy delivered per volume of tumor, E_(V) is:

E _(V) =E _(T) ×T _(H)/(N _(H) ×T _(V,before))  Equation 6

where N_(H) is the electrode height, which was about 5 millimeters.

Results of experiments carried out to treat skin lesions of mice are summarized in Table 1 to 4. In these tables or tables following them, “−” sign in front of the numerals shown in the tumor growth/shrinkage column represent shrinkage of the lesion. For example, “−85%” means 85% shrinkage. If there is no “−” sign in front of the numerals shown in the tumor growth/shrinkage column, it represents growth of the lesion. For example, “43%” means 43% growth.

TABLE 1 Electrical pulses applied to skin lesions and treatment results. Peak Electrical Pulse Amplitude Energy Duration of Delivered at Electrical Per Tumor FWHM Pulses Pulse Example Mouse Number Number (ns) (kV) (mJ) 3 SENCAR-C, 3 4 0 0.0 0.00 4 CD-1, 1 0 0.0 0.00 5 SENCAR-C, 1 2 0 0.0 0.00 6 CD-1, 2 1 0 0.0 0.00 7 CD-1, 2 2 0 0.0 0.00 8 SENCAR-C, 2 1 0 0.0 0.00 9 15 1 7 7.0 2.29 10 18 1 7 7.0 2.29 11 19 1 7 7.0 2.29 12 19 2 7 7.0 2.29 13 20 1 7 7.0 2.29 14 20 2 7 7.0 2.29 15 12 1 7 7.0 2.29 16 13 1 7 7.0 2.29 17 16 1 7 7.0 2.29 18 11 1 7 7.0 2.29 19 17 1 7 7.0 2.29 20 11 2 7 7.0 2.29 21 14 1 7 7.0 2.29 22 CD-1 1 14 5.5 2.82 23 1, R 1 14 5.5 2.82 24 CD-1, 2 1 14 5.5 2.82 25 CD-1, 3, R 1 14 5.5 2.82 25 SENCAR-C, 1 1 14 5.5 2.82 26 CD-1, 1, L 1 14 5.5 2.82 27 SENCAR-C, 1-R 2 14 7.0 4.57 28 CD-1, 1-R 1 14 7.0 4.57 29 SENCAR-C, 1 1 14 7.0 4.57 30 SENCAR-C, 1 2 14 7.0 4.57 Total Electrical Electrical Energy Energy Number of Applied Applied Electrical Number of per per Tumor Pulses per Applications Treatment Volume Example Application per Tumor (mJ) (mJ/mm³) 3 0 3 0 0 4 0 4 0 0 5 0 3 0 0 6 0 3 0 0 7 0 3 0 0 8 0 3 0 0 9 50 3 344 18 10 50 6 687 9 11 50 3 344 18 12 50 5 573 7 13 50 3 344 18 14 50 5 573 9 15 100 3 687 29 16 100 3 687 24 17 100 6 1374 18 18 200 3 1374 49 19 200 6 2748 24 20 400 5 4580 73 21 400 5 4580 73 22 200 4 2256 60 23 200 3 1692 60 24 200 4 2256 60 25 200 3 1692 72 25 200 5 2820 45 26 200 4 2256 52 27 50 4 914 28 28 50 4 914 24 29 50 3 686 35 30 50 3 686 29 Tumor Size One Week After Tumor Size Before Treatment Treatment Length Width Height Volume Length Width Height Volume Example (mm) (mm) (mm) (mm³) (mm) (mm) (mm) (mm³) 3 2.50 2.50 2.00 7.81 4.50 3.00 2.50 21.09 4 3.50 2.00 3.00 13.13 4.00 3.00 2.50 18.75 5 3.00 2.50 2.00 9.38 5.50 4.00 3.00 41.25 6 2.50 2.00 2.00 6.25 3.50 2.50 3.00 16.41 7 2.50 1.50 1.50 3.52 3.50 2.00 3.00 13.13 8 3.00 2.50 3.00 14.06 6.00 3.50 4.50 59.06 9 3.00 2.00 2.00 7.50 3.00 2.00 2.00 7.50 10 6.00 4.00 2.00 30.00 6.00 5.00 3.00 56.25 11 3.00 2.00 1.50 5.63 6.00 5.00 3.00 56.25 12 5.00 5.00 1.00 15.63 7.00 6.00 3.00 78.75 13 3.00 2.00 1.00 3.75 6.00 4.00 2.00 30.00 14 5.00 4.00 2.00 25.00 4.00 3.00 3.00 22.50 15 3.00 2.50 2.00 9.38 6.00 5.00 3.00 56.25 16 3.00 3.00 2.00 11.25 2.00 1.00 1.00 1.25 17 6.00 4.00 2.00 30.00 6.00 4.00 2.00 30.00 18 3.00 3.00 1.00 5.63 3.00 3.00 1.00 5.63 19 6.00 6.00 3.00 67.50 6.00 4.00 3.00 45.00 20 5.00 4.00 2.00 25.00 3.00 2.00 1.00 3.75 21 5.00 4.00 3.00 37.50 0.00 0.00 0.00 0.00 22 4.00 3.00 2.00 15.00 2.00 2.00 3.00 7.50 23 3.00 3.00 1.00 5.63 0.00 0.00 0.00 0.00 24 4.00 3.00 0.50 3.75 0.00 0.00 0.00 0.00 25 3.00 2.50 3.00 14.06 0.00 0.00 0.00 0.00 25 5.00 4.00 2.00 25.00 0.00 0.00 0.00 0.00 26 4.00 3.50 2.50 21.88 0.00 0.00 0.00 0.00 27 3.50 3.00 2.00 13.13 0.00 0.00 0.00 0.00 28 4.00 3.00 1.50 11.25 0.00 0.00 0.00 0.00 29 2.50 2.50 1.50 5.86 2.00 2.00 2.00 5.00 30 3.00 2.50 2.00 9.38 0.00 0.00 0.00 0.00 Tumor Growth or Shrinkage Example (%) Conclusions  3 170 Tumor grew  4 43 Tumor grew  5 340 Tumor grew  6 163 Tumor grew  7 273 Tumor grew  8 320 Tumor grew  9 0 Tumor volume not changed 10 88 Tumor grew 11 900 Tumor grew 12 404 Tumor grew 13 700 Tumor grew 14 −10 Tumor shrunk 15 500 Tumor grew 16 −89 Tumor shrunk 17 0 Tumor volume not changed 18 0 Tumor volume not changed 19 −33 Tumor shrunk 20 −85 Tumor shrunk 21 −100 Tumor cleared 22 −50 Tumor shrunk 23 −100 Tumor cleared 24 −100 Tumor cleared 25 −100 Tumor cleared 25 −100 Tumor cleared 26 −100 Tumor cleared 27 −100 Tumor cleared 28 −100 Tumor cleared 29 −15 Tumor shrunk 30 −100 Tumor cleared Peak Electrical Pulse Amplitude Energy Duration of Delivered at Electrical Per Tumor FWHM Pulses Pulse Example Mouse Number Number (ns) (kV) (mJ) 31 SENCAR-C, 1 3 14 7.0 4.57 32 SENCAR-C, 2 1 14 7.0 4.57 33 SENCAR-C, 1 2 14 7.0 4.57 34 SENCAR-C, 2 3 14 7.0 4.57 35 SENCAR-C, 3 2 14 7.0 4.57 36 SENCAR-C, 3 1 14 7.0 4.57 37 SENCAR-C, 1 1 14 7.0 4.57 38 SENCAR-C, 1 2 14 7.0 4.57 39 SENCAR-C, 2 1 14 7.0 4.57 40 SENCAR-C, 1 1 14 7.0 4.57 41 CD-1, 1 1 14 7.0 4.57 42 CD-1, 1 1 14 7.0 4.57 43 SENCAR-C, 1 1 14 7.0 4.57 44 SENCAR-C, 2 1 14 7.0 4.57 45 SENCAR-C, 2 2 14 7.0 4.57 46 CD-1, 2 1 14 7.0 4.57 47 CD-1, 1 1 14 7.0 4.57 48 CD-1, 1 1 14 7.0 4.57 49 SENCAR-C, 3 3 14 7.0 4.57 50 SENCAR-C, 2 3 14 7.0 4.57 51 SENCAR-C, 3, R 4 14 7.0 4.57 52 SENCAR-C, 1 14 7.0 4.57 53 SENCAR-C 1 14 7.0 4.57 54 CD-1, 1 1 14 7.0 4.57 55 CD-1, 3 1 14 7.0 4.57 56 SENCAR-C, 3 2 14 7.0 4.57 57 CD-1, 1 3 14 7.0 4.57 58 CD-1, 1 2 14 7.0 4.57 59 CD-1, 1, R 1 14 7.0 4.57 Total Electrical Electrical Energy Energy Number of Applied Applied Electrical Number of per per Tumor Pulses per Applications Treatment Volume Example Application per Tumor (mJ) (mJ/mm³) 31 50 5 1143 20 32 50 5 1143 18 33 200 6 5484 97 34 200 3 2742 117 35 200 5 4570 93 36 200 6 5484 80 37 200 2 1828 146 38 200 3 2742 117 39 200 3 2742 117 40 200 4 3656 97 41 200 5 4570 73 42 200 4 3656 84 43 200 5 4570 108 44 200 2 1828 146 45 200 4 3656 111 46 400 4 7312 195 47 400 6 10968 146 48 400 2 3656 292 49 400 3 5484 390 50 400 3 5484 234 51 400 4 7312 223 52 400 5 9140 167 53 400 4 7312 223 54 400 4 7312 267 55 400 5 9140 146 56 400 4 7312 223 57 400 5 9140 162 58 400 4 7312 195 59 400 3 5484 195 Tumor Size One Week After Tumor Size Before Treatment Treatment Length Width Height Volume Length Width Height Volume Example (mm) (mm) (mm) (mm³) (mm) (mm) (mm) (mm³) 31 4.50 4.00 3.50 39.38 0.00 0.00 0.00 0.00 32 5.00 4.00 3.00 37.50 0.00 0.00 0.00 0.00 33 6.00 3.00 3.00 33.75 0.00 0.00 0.00 0.00 34 3.00 2.50 2.00 9.38 0.00 0.00 0.00 0.00 35 4.50 3.50 2.00 19.69 0.00 0.00 0.00 0.00 36 5.50 4.00 3.00 41.25 1.50 1.50 0.00 0.00 37 2.00 2.00 1.50 3.75 0.00 0.00 0.00 0.00 38 3.00 2.50 2.00 9.38 0.00 0.00 0.00 0.00 39 3.00 2.50 1.00 4.69 0.00 0.00 0.00 0.00 40 4.00 3.00 1.00 7.50 0.00 0.00 0.00 0.00 41 5.00 4.00 3.00 37.50 0.00 0.00 0.00 0.00 42 4.00 3.50 4.00 35.00 0.00 0.00 0.00 0.00 43 4.50 3.00 2.50 21.09 0.00 0.00 0.00 0.00 44 2.00 2.00 2.00 5.00 0.00 0.00 0.00 0.00 45 3.50 3.00 2.50 16.41 0.00 0.00 0.00 0.00 46 4.00 3.00 3.00 22.50 0.00 0.00 0.00 0.00 47 6.00 4.00 2.00 30.00 0.00 0.00 0.00 0.00 48 2.00 2.00 2.00 5.00 0.00 0.00 0.00 0.00 49 3.00 1.50 2.00 5.63 0.00 0.00 0.00 0.00 50 3.00 2.50 2.00 9.38 0.00 0.00 0.00 0.00 51 3.50 3.00 1.50 9.84 0.00 0.00 0.00 0.00 52 5.00 3.50 3.00 32.81 0.00 0.00 0.00 0.00 53 3.50 3.00 2.00 13.13 0.00 0.00 0.00 0.00 54 3.50 2.50 3.00 16.41 2.50 1.50 1.50 3.52 55 5.00 4.00 3.00 37.50 0.00 0.00 0.00 0.00 56 3.50 3.00 1.50 9.84 0.00 0.00 0.00 0.00 57 4.50 4.00 3.00 33.75 0.00 0.00 0.00 0.00 58 4.00 3.00 2.50 18.75 0.00 0.00 0.00 0.00 59 3.00 3.00 2.00 11.25 0.00 0.00 0.00 0.00 Tumor Growth or Shrinkage Example (%) Conclusions 31 −100 Tumor cleared 32 −100 Tumor cleared 33 −100 Tumor cleared 34 −100 Tumor cleared 35 −100 Tumor cleared 36 −100 Tumor cleared, scab remained 37 −100 Tumor cleared 38 −100 Tumor cleared 39 −100 Tumor cleared 40 −100 Tumor cleared 41 −100 Tumor cleared 42 −100 Tumor cleared 43 −100 Tumor cleared 44 −100 Tumor cleared 45 −100 Tumor cleared 46 −100 Tumor cleared 47 −100 Tumor cleared 48 −100 Tumor cleared 49 −100 Tumor cleared 50 −100 Tumor cleared 51 −100 Tumor cleared 52 −100 Tumor cleared 53 −100 Tumor cleared 54 −79 Tumor shrunk 55 −100 Tumor cleared 56 −100 Tumor cleared 57 −100 Tumor cleared, scab remained 58 −100 Tumor cleared, scab remained 59 −100 Tumor cleared

In Examples 3 to 8, no electricity was applied. That is, all electrical pulse generator parameters, the pulse duration, the amplitude and the number of electrical pulses per application were set at zero. Only the applicator tip was inserted into the tumor as described above. As expected, the tumors grew in the range of 43% to 340%. In Example 3, no electricity was applied, although the tip was inserted into the tumor shown in FIG. 5. As shown in FIG. 6, this tumor grew in size one week after the treatment and the volume growth was about 170%. These experiments demonstrated that in the absence of electrical nanopulses, the tumor growth is not prevented by only mechanical penetration of the electrodes.

After the first day following the treatment with electrical nanopulses, the tumors became noticeably darkened, nearly black in some places. This dark hue persisted for about 5 days, after which the color changed to pink and then returned to normal skin color. When the tumor volume shrunk to a negligibly measurable size (i.e. about 100%), this shrinkage was recorded as “tumor cleared”. For some tumors, a scab like formation remained although their volume was determined to be negligible one week after the treatment. These scabs were flatter in shape, rough and hard in texture, and red in color. For the scabs, the shrinkage was recorded as “tumor cleared, but scab remained”. In some treatments, the tumors did not shrink, but at the same time, they did not grow; that is about 0%. Thus, the tumor growth was prevented. For these treatments, the results were recorded as “tumor volume not changed”.

As shown in Table 2, when the electrical energy applied per tumor volume was in the range of about 7.3 mJ/mm³ to about 18.3 mJ/mm³, the effect of electrical nanopulses on the tumor growth was negligible except in Example 32. In this electrical energy range, in examples 10-13, the tumors continued to grow. In examples 9 and 17, the tumor growth was prevented. In Example 14, the tumor shrinkage was negligible. However, in Example 32, the tumor was cleared at the energy of about 18.3 mJ/mm³.

These examples summarized in Table 2 demonstrated that onset of electrical energy required for a successful treatment of skin lesions was about 18.3 mJ/mm³. Below this energy level, the treatment was not effective.

TABLE 2 Electrical pulses applied to skin lesions and treatment results. Peak Electrical Pulse Amplitude Energy Duration of Number of Applied Tumor at Electrical Electrical per Tumor Growth or FWHM Pulses Pulses per Volume Shrinkage Example (ns) (kV) Application (mJ/mm³) (%) Notes 9 7 7.00 50 18.3 0 Tumor volume not changed 10 7 7.00 50 9.2 88 Tumor grew 11 7 7.00 50 18.3 900 Tumor grew 12 7 7.00 50 7.3 404 Tumor grew 13 7 7.00 50 18.3 700 Tumor grew 14 7 7.00 50 9.2 −10 Tumor shrunk 17 7 7.00 100 18.3 0 Tumor volume not changed 32 14 7.00 50 18.3 −100 Tumor cleared

These examples summarized in Table 2 further demonstrated that the skin lesion treatment may be more effective at pulse duration of about 14 ns at FWHM than at a pulse duration of about 7 ns at FWHM. However, in Examples 9 and 17, at least the tumor growth was prevented at an energy level of about 18.3 mJ/mm³ for the pulse duration of about 7 ns at FWHM. These results suggested that the skin lesions may be cleared by having more than one treatment at this pulse duration level; for example, by having a second treatment one week after the first. For such treatments, a pulse duration of about 7 ns at FWHM may be used.

As shown in Table 3, when the electrical energy applied per tumor volume was in the range of about 20.3 mJ/mm³ to about 48.9 mJ/mm³, the tumors shrunk at least 15% for 80% of the cases. At this energy level, the tumor growth was prevented in Example 18 by applying electrical pulses with duration of about 7 nanoseconds at FWHM.

The examples summarized Table 3 demonstrated that the skin lesion treatment may be more effective at the pulse duration of about 14 ns at FWHM than at the pulse duration of about 7 ns at FWHM. However, as explained above, at least the tumor growth can be prevented with the pulse duration of about 7 ns at FWHM and more than one treatment is possible.

TABLE 3 Electrical pulses applied to skin lesions and treatment results. Peak Electrical Pulse Amplitude Energy Duration of Number of Applied Tumor at Electrical Electrical per Tumor Growth or FWHM Pulses Pulses per Volume Shrinkage Example (ns) (kV) Application (mJ/mm³) (%) Notes 15 7 7.00 100 29.3 500 Tumor grew 16 7 7.00 100 24.4 −89 Tumor shrunk 18 7 7.00 200 48.9 0 Tumor volume not changed 19 7 7.00 200 24.4 −33 Tumor shrunk 25 14 5.50 200 45.1 −100 Tumor cleared 27 14 7.00 50 27.9 −100 Tumor cleared 28 14 7.00 50 24.4 −100 Tumor cleared 29 14 7.00 50 35.1 −15 Tumor shrunk 30 14 7.00 50 29.2 −100 Tumor cleared 31 14 7.00 50 20.3 −100 Tumor cleared

As shown in Table 4, when the electrical energy applied per tumor volume was above about 51.6 mJ/mm³, the tumors shrunk at least 50% for all the cases, i.e. 34 cases. In this energy level, the tumors were cleared in more than 90% of the cases. For example, the tumor of Example 36, shown in FIG. 5, cleared within one week, i.e. 100% reduction in volume, after it was treated by applying an electrical energy of about 79.8 mJ/mm³. As shown in FIG. 6, only a scab remained after this treatment.

TABLE 4 Electrical pulses applied to skin lesions and treatment results. Electrical Pulse Amplitude Energy Duration of Number of Applied Tumor at Electrical Electrical per Tumor Growth or FWHM Pulses Pulses per Volume Shrinkage Example (ns) (kV) Application (mJ/mm³) (%) Notes 20 7 7.00 400 73.3 −85 Tumor shrunk 21 7 7.00 400 73.3 −100 Tumor cleared 22 14 5.50 200 60.2 −50 Tumor shrunk 23 14 5.50 200 60.2 −100 Tumor cleared 24 14 5.50 200 60.2 −100 Tumor cleared 25 14 5.50 200 72.2 −100 Tumor cleared 26 14 5.50 200 51.6 −100 Tumor cleared 33 14 7.00 200 97.5 −100 Tumor cleared 34 14 7.00 200 117.0 −100 Tumor cleared 35 14 7.00 200 92.9 −100 Tumor cleared 36 14 7.00 200 79.8 −100 Tumor cleared, but scab remained 37 14 7.00 200 146.2 −100 Tumor cleared 38 14 7.00 200 117.0 −100 Tumor cleared 39 14 7.00 200 117.0 −100 Tumor cleared 40 14 7.00 200 97.5 −100 Tumor cleared 41 14 7.00 200 73.1 −100 Tumor cleared 42 14 7.00 200 83.6 −100 Tumor cleared 43 14 7.00 200 108.3 −100 Tumor cleared 44 14 7.00 200 146.2 −100 Tumor cleared 45 14 7.00 200 111.4 −100 Tumor cleared 46 14 7.00 400 195.0 −100 Tumor cleared 47 14 7.00 400 146.2 −100 Tumor cleared 48 14 7.00 400 292.5 −100 Tumor cleared 49 14 7.00 400 390.0 −100 Tumor cleared 50 14 7.00 400 234.0 −100 Tumor cleared 51 14 7.00 400 222.8 −100 Tumor cleared 52 14 7.00 400 167.1 −100 Tumor cleared 53 14 7.00 400 222.8 −100 Tumor cleared 54 14 7.00 400 267.4 −79 Tumor shrunk 55 14 7.00 400 146.2 −100 Tumor cleared 56 14 7.00 400 222.8 −100 Tumor cleared 57 14 7.00 400 162.5 −100 Tumor cleared, but scab remained 58 14 7.00 400 195.0 −100 Tumor cleared, but scab remained 59 14 7.00 400 195.0 −100 Tumor cleared

Examples 60 to 77. Application of Nanosecond Electrical Pulses to Warts

In Examples 60 to 74, common warts, which formed on the skins of human subjects, were treated by using the nanopulse generator and the applicator tip manufactured in the same manner disclosed in Example 1. An open label, non-randomized clinical study was carried out at two study sites to achieve these treatments. Licensed dermatologists treated 15 human subjects. The Food and Drug Administration (FDA) regulations, rules and guidances were followed to manufacture the device and carry out these clinical studies.

Following inclusion criteria were applied in these Examples. Subject must be 18 years of age or older at enrollment. Only common warts are included as study lesions. Up to 2 discrete common warts in a single about 5 cm×about 5 cm anatomical area can be included as study lesions, with up to 2 distinct 5 cm×5 cm areas included. The 5 cm×5 cm area must not have more than 2 warts present at the time of screening and warts outside each area must be at least 2 cm away from warts included as study lesions. A single digit (e.g. finger) can represent the 5 cm×5 cm area, and a lesion within the area can be included as a study lesion unless it is on the inside surface of a digit where there are wart lesions present on the surface of an adjacent digit that would be within 1 cm of touching the potential study lesion when the surfaces of the digits are in contact with one another. Subject's lesions must not protrude more than 5 mm from the skin surface. Subject's lesions may have been treated with over-the-counter treatments, but not by any prescription medicine, surgery, or destructive procedure (i.e., cryotherapy). Subjects' wart and the subject must be suitable candidates for usual Standard of Care treatments. Standard of Care for common warts is defined as curettage and electrodessication, cryotherapy, topical therapy or surgery. Subject must be competent to provide informed consent. If the subject is female, and of childbearing potential, subject must be actively practicing a clinically acceptable form of birth control. Subjects' medical evaluation during their screening visit does not indicate any findings of clinical significance relevant to participating in study. Subject has been informed of their options for standard of care for the lesion type outside of the study.

Following exclusion criteria were applied in these Examples. Subjects not meeting all inclusion criteria should be excluded. Subjects who have lesions within the 5 cm×5 cm anatomical area under study that are painful or have been noticeably changing just prior to the time of screening are excluded. Common wart lesions which are recalcitrant and have not responded to previous office therapy are excluded from the study as study lesions. Periungual warts are excluded from the study as study lesions. Lesions on the face are excluded from the study as study lesions. Lesions which are diagnosed as flat warts, filiform warts, plantar warts, and genital warts are excluded from the study as study lesions. Subjects who are using or intend to use any other warts therapy concomitantly during the study period or within 30 days of their screening visit are excluded. Subjects who are not capable of undergoing surgical standard of care treatment for common warts due to mental or physical limitations are excluded. Subjects in whom a minor surgical procedure is contraindicated (e.g. under advice of their own caring physician) are excluded. Subjects who have an implanted artificial heart valve or other prosthesis requiring prophylactic antibiotic coverage for minor surgical procedures are excluded. Subjects who have an implanted cardiac pacer or defibrillator or other similar life sustaining implanted electrical device are excluded. Subjects who have had any cosmetic or therapeutic procedure (e.g. use of liquid nitrogen, surgical excision, curettage, dermabrasion, medium or greater depth chemical peel, laser resurfacing) within 2 cm of targeted area and margins within 30 days of the screening visit are excluded. Subjects who are immunosuppressed either due to an existing medical diagnosis, or are currently using medications that suppress the immune system (e.g. cyclosporine, prednisone, methotrexate, alefacept, infliximab) or have used these medications within 30 days of the screening visit are excluded. Subjects who, if female, know that they are currently pregnant or are lactating and actively breastfeeding are excluded. Under the Investigator's authority to exclude any participant at his/her discretion, participation in this study is not recommended for this subject.

The restrictions, limitations, exceptions and time periods shown in Table 5 were followed by all subjects upon enrolling and for the duration of the study.

TABLE 5 Restrictions, time periods, limitations and exceptions for the wart studies. Restrictions Time Periods, Limitations and Exceptions Any cosmetic or therapeutic procedure (e.g. use Within 2 cm of targeted area and margins during of liquid nitrogen, surgical excision, curettage, 4 weeks prior to screening visit dermabrasion, medium or greater depth chemical Within 10 cm of Nanopulse Application area peel, laser resurfacing) during the study Hair removal procedures, including wax, cremes, Within 2 cm of Nanopulse Application area within laser etc. 30 days of screening visit Within 2 cm of the lesion locations during the study 5-Fluorouracil, imiquimod, diclofenac, Within 10 cm of the Nanopulse application area masoarocol, or photodynamic therapy during the study. Acid-containing therapeutic products (e.g. Within 2 cm of lesion location during 30 days prior salicylic acids or fruit acids, such as α and β to screening visit hydroxy acids and glycolic acids), topical retinoids Within 2 cm of Nanopulse Application area during or light chemical peels the study Medications that suppress the immune system Within 30 days prior to screening visit or anytime (e.g. cyclosporine, prednisone, methotrexate, during the study alefaceat, infliximab) Excessive or prolonged exposure to ultraviolet Anytime during the study light (e.g. sunlight, tanning booths) Topical creams, gels, lotions, oils, artificial Anytime during study to Nanopulse Application tanners, or topical steroids area Any medications or treatments that might Anytime during study influence the intended effects or mask the side effects of Nanopulse Application, such as the application of topical steroids to the Nanopulse Application area

The ground and delivery electrodes had the same length for the same applicator tip. The applicator tips with their electrode length varying in the range of 2 mm to 5 mm were used in the treatments. For the application, whole electrode was inserted in the wart. For example, for about 5 mm long electrodes, insertion length of the electrode was about 5 mm for each delivery of the electrical nanopulses. To avoid formation of air pockets between the electrodes, both the tumor and the electrodes were covered with Aquasonic 100 ultrasound transmission gel.

Treatment procedure comprised one or more treatment sessions per wart per subject. Also, each treatment comprised one or more applications per wart. In each application, about 3200 electrical pulses were applied to each wart with a repetition rate (i.e. frequency) of about 100 Hz. The pulse duration was about 18 ns at FWHM and the pulse amplitude was about 7 kV. Then, for R_(L) of about 100 ohms, the total energy delivered to the tissue per pulse was calculated to be about 5.88 mJ.

The wart size was measured by using a ruler. The highest elevation of the wart as measured from the healthy skin surface (i.e. protrusion) was recorded as the wart height. The longest length of the wart as measured parallel to the healthy skin surface was recorded as the wart diameter. The wart volume, Wa_(V) was then calculated by using the following equation:

Wa _(V)=0.625×(π×Wa _(D) ²/4)×Wa _(H)  Equation 7

where Wa_(D) is the wart diameter and Wa_(H) is the wart height. The percent of wart growth or shrinkage after each treatment, Wa_(C) is:

Wa _(C)=100×(Wa _(V,after) −Wa _(V,before))/Wa _(V,before)  Equation 8

where Wa_(V,after) is the wart volume measured after the treatment and Wa_(V,before) is the wart volume measured before the treatment.

The pulse duration at FWHM, the pulse amplitude, and the number of pulses per application were set on the pulse generator. Then, the electrodes were vertically inserted into the wart and the electrical pulses were applied.

Surface of the warts, facing the applicator tip, was generally round. Locations for insertion of the delivery electrode were visually decided and evenly distributed on this surface.

The total electrical energy delivered by the applicator tip per treatment, E_(T) is:

E _(T) =E _(P) ×N _(P) ×A _(N)  Equation 9

where N_(P) is the number of pulses per application and A_(N) is number of applications per wart. Electrical energy delivered per volume of wart, E_(V) is:

E _(V) =E _(T) ×Wa _(H)/(N _(H) ×Wa _(V,before))  Equation 10

where N_(H) is the electrode height.

The applicator tips are designed for single patient use and sterilized between each treatment by using a standard steam autoclave.

Results of the clinical trials are summarized in Table 6. In this table, “NA” means not available.

TABLE 6 Treatment of common warts. Electrode Screening Visit Subject Length Diam. Height Volume Example ID (mm) Date Wart Location (mm) (mm) (mm³) 60 01-207 5.00 Dec. 19, 2011 Right middle finger, 5.00 1.00 12.27 posterior 61 01-208 5.00 Feb. 21, 2012 Dorsal near pinky finger 8.00 1.00 31.42 below knuckle 62 01-209 5.00 Feb. 29, 2012 Left hand, posterior, 10.00 3.00 147.26 near pinky knuckle 63 01-210 5.00 Mar. 5, 2012 Abdomen 4.00 1.00 7.85 64 02-205 5.00 Mar. 12, 2012 Righ hand, anterior 8.00 3.00 94.25 knuckle near ring finger 65 01-204 5.00 Jan. 16, 2012 Left leg, anterior, 5.00 1.00 12.27 66 01-201 4.00 Oct. 27, 2011 Left index finger 5.00 1.00 12.27 67 01-203 4.00 Nov. 15, 2011 Left hand, anterior 2.00 1.00 1.96 68 01-201 4.00 Oct. 27, 2011 Left fourth finger 6.00 1.00 17.67 69 01-203 4.00 Nov. 15, 2011 Left hand, anterior 3.00 1.00 4.42 70 01-205 5.00 Jan. 24, 2012 Right hand, side of 4.00 1.00 7.85 pinky finger 71 01-206 5.00 Jan. 31, 2012 Right thumb, medial, 5.00 1.00 12.27 anterior 72 02-203 4.00 Nov. 28, 2011 Left posterior hand 6.00 3.00 53.01 73 02-203 4.00 Nov. 28, 2011 Right hand, side of 3.00 1.00 4.42 thumb 74 02-204 4.00 Dec. 8, 2011 Left lower leg 7.00 1.00 24.05 75 01-202 2.00 Nov. 7, 2011 Left fourth finger 2.00 2.00 3.93 76 02-201 5.00 Oct. 26, 2011 Right hand 4.00 1.50 11.78 77 02-202 4.00 Nov. 8, 2011 Right posterior arm, 4.50 2.00 19.88 Treatment 1 Electrical Number of Energy Applications Applied per per Wart Wart Volume Example Date (#) (mj/mm³) 60 Feb. 16, 2012 4 1227 61 Feb. 15, 2012 12 1437 62 Mar. 1, 2012 12 920 63 Mar. 9, 2012 6 2875 64 Mar. 12, 2012 16 1917 65 Jan. 27, 2012 5 1533 66 Nov. 9, 2011 4 1533 67 Nov. 29, 2011 1 2396 68 Nov. 9, 2011 5 1331 69 Nov. 29, 2011 2 2130 70 Feb. 13, 2012 5 2396 71 Feb. 15, 2012 3 920 72 Nov. 28, 2011 10 2662 73 Nov. 28, 2011 8 8518 74 Dec. 8, 2011 11 1721 75 Nov. 14, 2011 4 19166 76 Oct. 26, 2011 11 5271 77 Nov. 8, 2011 10 4732 Treatment 2 Electrical Energy Evaluation before Treatment 2 Number of Applied Growth/ Applications per Wart Diam. Height Volume Shrink. per Wart Volume Example (mm) (mm) (mm³) (%) Date (#) (mj/mm³) 60 NA NA NA NA No treatment 61 NA NA NA NA No treatment 62 NA NA NA NA No treatment 63 NA NA NA NA No treatment 64 NA NA NA NA No treatment 65 0.00 0.00 0.00 −100 Mar. 15, 2012 No treatment 66 0.00 0.00 0.00 −100 Nov. 22, 2011 No treatment 67 0.00 0.00 0.00 −100 Dec. 13, 2011 No treatment 68 5.00 0.10 1.23 −93 Nov. 22, 2011 4 1533 69 3.00 0.10 0.44 −90 Dec. 13, 2011 1 1065 70 3.00 0.50 2.21 −72 Mar. 9, 2012 4 3407 71 2.00 0.50 0.98 −92 Mar. 15, 2012 4 7666 72 6.00 0.10 1.77 −97 Dec. 14, 2011 11 2928 73 2.00 0.10 0.20 −96 Dec. 14, 2011 6 14374 74 6.00 1.00 17.67 −27 Dec. 15, 2011 10 2130 75 4.00 0.10 0.79 −80 Nov. 28, 2011 4 4791 76 3.50 1.00 6.01 −49 Nov. 3, 2011 11 6884 77 4.00 2.00 15.71 −21 Nov. 15, 2011 10 5989 Treatment 3 Electrical Energy Evaluation before Treatment 3 Number of Applied Growth/ Applications per Wart Diam. Height Volume Shrink. per Wart Volume Example (mm) (mm) (mm³) (%) Date (#) (mj/mm³) 60 NA NA NA NA No treatment 61 NA NA NA NA No treatment 62 NA NA NA NA No treatment 63 NA NA NA NA No treatment 64 NA NA NA NA No treatment 65 NA NA NA NA No treatment 66 NA NA NA NA No treatment 67 NA NA NA NA No treatment 68 NA NA NA NA No treatment 69 NA NA NA NA No treatment 70 NA NA NA NA No treatment 71 NA NA NA NA No treatment 72 NA NA NA NA No treatment 73 NA NA NA NA No treatment 74 NA NA NA NA No treatment 75 4.00 0.10 0.79 −80 Dec. 12, 2011 4 4791 76 3.00 1.00 4.42 −63 Nov. 10, 2011 10 8518 77 0.00 0.00 0.00 −100 Nov. 29, 2011 10 NA Day 45 Evaluation Growth/ Diam. Height Volume Shrink. Example Date (mm) (mm) (mm³) (%) 60 Mar. 29, 2012 4.00 0.50 3.93 −68 61 Apr. 10, 2012 4.00 1.00 7.85 −75 62 Apr. 17, 2012 12.00 3.00 212.06 44 63 Apr. 23, 2012 5.00 0.50 6.14 −22 64 Apr. 23, 2012 8.00 6.00 188.50 100 65 Mar. 21, 2012 0.00 0.00 0.00 −100 66 Dec. 22, 2011 0.00 0.00 0.00 −100 67 Jan. 13, 2012 1.50 0.10 0.11 −94 68 Dec. 22, 2011 4.00 0.10 0.79 −96 69 Jan. 13, 2012 2.00 0.10 0.20 −96 70 Mar. 30, 2012 3.00 0.50 2.21 −72 71 Apr. 4, 2012 2.00 0.50 0.98 −92 72 Jan. 11, 2012 3.00 0.10 0.44 −99 73 Jan. 11, 2012 3.00 0.10 0.44 −90 74 Jan. 25, 2012 0.00 0.00 0.00 −100 75 Jan. 4, 2012 5.00 1.00 12.27 213 76 Dec. 8, 2011 0.00 0.00 0.00 −100 77 Dec. 22, 2011 0.00 0.00 0.00 −100 Day 90 Evaluation Duration after Day Number Growth/ 45 of Treat. Diam. Height Vol. Shrink Evaluation Sessions Ex. Date (mm) (mm) (mm³) (%) (days) (#) Concln. 60 May 21, 2012 4.00 0.50 3.93 −68 53 1 Substantial shrinkage 61 May 21, 2012 5.00 1.00 12.27 −61 41 1 Substantial shrinkage 62 Jun. 11, 2012 12.00 2.00 141.37 −4 55 1 No change 63 Jun. 6, 2012 5.00 1.00 12.27 56 44 1 Growth 64 Jun. 11, 2012 10.00 4.00 196.35 108 49 1 Substantial growth 65 May 4, 2012 0.00 0.00 0.00 −100 44 1 Cleared 66 Feb. 3, 2012 0.00 0.00 0.00 −100 43 1 Cleared 67 Feb. 27, 2012 1.50 0.10 0.11 −94 45 1 Substantial shrinkage 68 Feb. 3, 2012 0.00 0.00 0.00 −100 43 2 Cleared 69 Feb. 27, 2012 3.00 0.50 2.21 −50 45 2 Substantial shrinkage 70 May 4, 2012 6.00 0.25 4.42 −44 35 2 Shrinkage 71 May 23, 2012 0.00 0.00 0.00 −100 49 2 Cleared 72 Feb. 22, 2012 3.00 1.00 4.42 −92 42 2 Substantial shrinkage 73 Feb. 22, 2012 2.50 1.00 3.07 −31 42 2 Shrinkage 74 Mar. 7, 2012 1.00 0.10 0.05 −100 42 2 Substantial shrinkage 75 Feb. 13, 2012 4.00 1.00 7.85 100 40 3 Substantial growth 76 Jan. 26, 2012 0.00 0.00 0.00 −100 49 3 Cleared 77 Feb. 6, 2012 0.00 0.00 0.00 −100 46 3 Cleared

In Examples 60 to 67, the treatment comprised one treatment session (“Treatment 1”). In Examples 68 to 74, two such treatment sessions per wart were carried out. Second treatment session, “Treatment 2” was carried out after a time interval varying in the range of about 7 days to about 48 days after Treatment 1. In Examples 75 to 77, three such treatment sessions were carried out at pre-determined time intervals between each treatment session. “Day 90 Evaluation” was carried out about 81 days to about 102 days after Treatment 1.

When the wart volume shrunk to a negligible size (i.e. about 100% shrinkage), it was concluded that the wart was “cleared”. In some treatments, the warts did not shrink, but at the same time, they did not grow; that is the wart growth or shrinkage was less than 10%. In these treatments, the wart growth was prevented and the results were recorded as “no change”. In examples where the wart shrinkage was in the range of >10% and <50%, it was concluded that there was “shrinkage”. In examples where the wart shrinkage was in the range of >50% and <100%, it was concluded that there was “substantial shrinkage”. If the wart growth was in the range of >10% to <100%, it was concluded that there was “growth”. And if the wart growth was >100%, it was concluded that there was “substantial growth”.

In Examples 68, 69, 72, 73 and 75, the height of the warts, which was measured at the evaluation stage before Treatment 2, was negligibly small, i.e. about 0 mm. The wart height for these examples was recorded as about 0.1 mm. Also, in Example 75, the height of the wart, which was measured at the evaluation stage before Treatment 3, was negligibly small, i.e. about 0 mm. The wart height for this example was recorded as about 0.1 mm. Furthermore, in Examples 67-69, 72 and 73, the height of the warts, which was measured at “Day 45 Evaluation”, was negligibly small, i.e. about 0 mm. The wart height for these examples was recorded as about 0.1 mm. Similarly, in Examples 67, 69 and 74, the height of the warts, which was measured at “Day 90 Evaluation”, was negligibly small, i.e. about 0 mm. The wart height for these examples was also recorded as about 0.1 mm.

All warts shrunk at least 21% after Treatment 1 in all examples where the wart sizes were measured before Treatment 2. These were Examples 65 to 77, i.e. 13 warts in total. The shrinkage was more than 70% for 10 out of these 13 warts (i.e. substantial shrinkage for at least 77% of the cases). And the warts were cleared for three out of these 13 warts (i.e. clearance for at least 20% of the cases). After a single treatment session, when the application energy was at least 920 mJ/mm³, the shrinkage was at least 21% for all warts treated, at least 40% for 85% of the warts treated, and at least 70% for 77% of the warts treated. These results indicated that the electrical energy applied to the wart in one electrical nanopulse treatment session may prevent growth or induce shrinkage of the common warts. These results further indicated that the electrical energy applied to the wart in one electrical nanopulse treatment session may clear the common warts for at least 20% of the cases.

In Examples 60 to 67, only one treatment session was carried out to treat 8 warts in total. The growth was prevented for 6 out of 8 warts (i.e. for at least 75% of cases). The shrinkage was at least 56% for 5 out of 8 warts (i.e. substantial shrinkage for at least 63% of the cases). And the warts were cleared for two out of 8 warts (i.e. clearance for at least 25% of the cases). After the only one treatment session, when the application energy was at least 920 mJ/mm³, the wart growth was at least prevented for at least 75% of cases. And the wart shrinkage was at least 56% for at least 63% cases. These results indicated that one electrical nanopulse treatment may at least prevent growth for at least 75% of cases or induce shrinkage of the common warts for at least 63% cases. These results further indicated that one electrical nanopulse treatment may clear the common warts for at least 25% of the cases.

In Examples 65 to 67, as observed before Treatment 2, the warts were cleared. Therefore, the second treatment session was not carried out in these examples. It was concluded that these warts were cleared with one treatment session.

In Examples 68 to 74, two treatment sessions were carried out to treat 7 warts in total. Day 90 evaluation indicated that at least 31% shrinkage was induced for all these 7 warts (i.e. for 100% cases); at least 50% shrinkage was induced for at least 5 warts out of 7 warts (i.e. substantial shrinkage for at least 71% of cases); and the warts were cleared for at least 2 warts (i.e. for at least 29% of the cases).

In Examples 75 to 77, three treatment sessions were carried out to treat 3 warts in total. Day 90 evaluation indicated that the warts cleared for 2 warts (i.e. for at least 67% of the cases).

Examples 68 to 77 indicated that more than one treatment session may be used to at least prevent growth, or induce shrinkage or clear common warts.

All wart sizes were also measured at “Day 45 Evaluation”. Following were concluded when wart sizes measured at “Day 45 Evaluation” were compared with those measured at “Day 90 Evaluation”. For 14 out 18 warts (i.e. 78% of the cases), the nanopulse electric treatment induced at least shrinkage that lasted at least 35 days. For example, in Example 60, the shrinkage was 68% as determined at “Day 45 Evaluation”. And 53 days after “Day 45 Evaluation”, this shrinkage was still 68% as determined at “Day 90 Evaluation”. These results indicated that the nanopulse electric treatment may at least prevent growth of the lesion that may last for a duration of at least 35 days. These results further indicated that the nanopulse electric treatment may induce at least shrinkage, or at least substantial shrinkage, or clearance that may last for a duration of at least 35 days. In Examples 60 to 67, the warts were treated with only one treatment session. For these examples, the treatment induced at least substantial shrinkage for 5 out of 8 warts (i.e. about 63% of the cases) that lasted for a duration of at least 41 days. These results indicated that the nanopulse electric treatment comprising only one session may at least prevent growth of the lesion that may last for a duration of at least 41 days. These results further indicated that the nanopulse electric treatment may induce at least shrinkage, or at least substantial shrinkage or clearance that may last for a duration of at least 41 days.

Examples 78 to 87. Application of Nanosecond Electrical Pulses to Actinic Keratosis

In Examples 78 to 87, actinic keratoses, which formed on the skins of human subjects, were treated by using the nanopulse generator and the applicator tip manufactured in the same manner disclosed in Example 1. An open label, non-randomized clinical study was carried out at two study sites to achieve these treatments. Licensed dermatologists treated 10 human subjects. The Food and Drug Administration regulations, rules and guidances were followed to manufacture the device and carry out these clinical studies.

Following inclusion criteria were applied in these Examples. Subject must be 18 years of age or older at enrollment. Primary (non-recurrent), clinically diagnosed actinic keratosis lesions on the scalp, dorsal portions of the hands and dorsal portions of the arms are included. Up to 2 discrete actinic keratosis lesions in a single about 5 cm×about 5 cm anatomical area are included as study lesions, with up to 2 distinct 5 cm×5 cm areas included (up to 4 lesions total). Each 5 cm×5 cm area must not have more than 2 actinic keratosis lesions present at the time of screening and lesions outside each area must be at least 10 mm away from those included as study lesions. Subject's study lesions must be separate from other visible lesions by at least 10 mm. Subjects' actinic keratosis and the subject must be suitable candidates for usual Standard of Care treatments. Standard of care for Actinic Keratosis is defined as cryotherapy. Subject must be competent to provide informed consent. If the subject is female, and of childbearing potential, subject must be actively practicing a clinically acceptable form of birth control. Subjects' medical evaluation during their screening visit does not indicate any findings of clinical significance relevant to participating in study. Subject has been informed of their options for standard of care for the lesion type outside of the study.

Following exclusion criteria were applied in these Examples. Subjects not meeting all inclusion criteria should be excluded. Subject's lesions which have been treated in the past with any modality shall be excluded from the study. Lesions which are painful or noticeably changing shall be excluded from the study. Lesions which are bleeding, weeping or ulcerated shall be excluded from the study. Marked hyperkeratotic, hypertrophic or confluent lesions shall be excluded from the study. No field therapy (such as photodynamic therapy or topical therapeutics) used in the same anatomical area 6 months prior to or during study period. Subjects who have had any cosmetic or therapeutic procedure (e.g. use of liquid nitrogen, surgical excision, curettage, dermabrasion, medium or greater depth chemical peel, laser resurfacing) within 2 cm of targeted lesion area and margins within 30 days of the screening visit. Subjects who are not capable of undergoing surgical standard of care treatment for actinic keratosis due to mental or physical limitations are excluded. Subjects in whom a minor surgical procedure is contraindicated (e.g. under advice of their own caring physician) are excluded. Subjects who have an implanted artificial heart valve or other prosthesis requiring prophylactic antibiotic coverage for minor surgical procedures are excluded. Subjects who have an implanted cardiac pacer or defibrillator or other similar life sustaining implanted electrical device are excluded. Subjects who are immunosuppressed either due to an existing medical diagnosis, or are currently using medications that suppress the immune system (e.g. cyclosporine, prednisone, methotrexate, alefacept, infliximab or any biologics associated with immune suppression) or have used these medications within 30 days of the screening visit are excluded. Subjects who, if female, know that they are currently pregnant or are lactating and actively breastfeeding are excluded. Under the Investigator's authority to exclude any participant at his/her discretion, participation in this study is not recommended for this subject.

The restrictions, limitations, exceptions and time periods shown in Table 7 were followed by all subjects upon enrolling and for the duration of the study.

TABLE 7 Restrictions, time periods, limitations and exceptions for the wart studies. Restrictions Time Periods, Limitations and Exceptions Any cosmetic or therapeutic procedure (e.g. use Within 2 cm of targeted area and margins during of liquid nitrogen, surgical excision, curettage, 4 weeks prior to screening visit dermabrasion, medium or greater depth chemical Within 5 cm of Nanopulse study lesion locations peel, laser resurfacing) during the study (except for liquid nitrogen for those study lesions which will be treated using cryotherapy) Hair removal procedures, including wax, cremes, Within 2 cm of Nanopulse Application area within laser etc. 30 days of screening visit Within 2 cm of the lesion locations during the study 5-Fluorouracil, imiquimod, diclofenac, Within 10 cm of the Nanopulse application area masoprocol, or photodynamic therapy during the study. Acid-containing therapeutic products (e.g. Within 2 cm of lesion location during 30 days prior salicylic acids or fruit acids, such as α and β to screening visit hydroxy acids and glycolic acids), topical retinoids Within 2 cm of Nanopulse Application area during or light chemical peels the study Medications that suppress the immune system Within 30 days prior to screening visit or anytime (e.g. cyclosporine, prednisone, methotrexate, during the study alefacept, infliximab, or any biologics associated with immune suppression) Excessive or prolonged exposure to ultraviolet Anytime during the study light (e.g. sunlight, tanning booths) Topical creams, gels, lotions, oils, artificial Anytime during study to Nanopulse Application tanners, or topical steroids area Any medications or treatments that might Anytime during study influence the intended effects or mask the side effects of Nanopulse Application, such as the application of topical steroids to the Nanopulse Application area

The ground and delivery electrodes had the same length for the same applicator tip. The applicator tips with their electrode lengths varying in the range of 2 mm to 5 mm were used in the treatments. For the application, whole electrode was inserted in the wart. For example, for about 5 mm long electrodes, insertion length of the electrode was about 5 mm for each delivery of the electrical nanopulses. To avoid formation of air pockets between the electrodes, both the tumor and the electrodes were covered with Aquasonic 100 ultrasound transmission gel.

Treatment procedure comprised one treatment session per actinic keratosis per subject. Each treatment session comprised one or more applications per actinic keratosis. In each application, about 3200 electrical pulses were applied to each actinic keratosis with a repetition rate (i.e. frequency) of about 100 Hz. The pulse duration was about 18 ns at FWHM and the pulse amplitude was about 7 kV. Then, for R_(L) of about 100 ohms, the total energy delivered to the tissue per pulse was calculated to be about 5.88 mJ.

The actinic keratosis size was measured by using a ruler. The elevation of the actinic keratosis as measured from the healthy skin surface (i.e. protrusion or height) was negligible, i.e. about 0 mm for all subjects. These heights were recorded as about 0.1 mm. The longest length of the actinic keratosis as measured parallel to the healthy skin surface was recorded as the actinic keratosis diameter. The actinic keratosis volume, AK_(v) was then calculated by using the following equation:

AK _(v)=0.625×(π×AK _(D) ²/4)×AK _(H)  Equation 11

where AK_(D) is the actinic keratosis diameter and AK_(H) is the actinic keratosis height. The percent of actinic keratosis growth or shrinkage after each treatment, AK_(C) is:

AK _(C)=100×(AK _(v,after) −AK _(v,before))/AK _(v,before)  Equation 12

where AK_(v,after) is the actinic keratosis volume measured after the treatment and AK_(v,before) is the actinic keratosis volume measured before the treatment.

The pulse duration at FWHM, the pulse amplitude, and the number of pulses per application were set on the pulse generator. Then, the electrodes were vertically inserted into the actinic keratosis and the electrical pulses were applied.

Surface of the actinic keratoses, facing the applicator tip, was generally round. Locations for insertion of the delivery electrode were visually decided and evenly distributed on this surface.

The total electrical energy delivered by the applicator tip per treatment, E_(T) is:

E _(T) =E _(P) ×N _(P) ×A _(N)  Equation 13

where N_(P) is the number of pulses per application and A_(N) is number of applications per actinic keratosis. Electrical energy delivered per volume of actinic keratosis, E_(V) is:

E _(V) =E _(T) /AK _(v,before)  Equation 14

where N_(H) is the electrode height.

The applicator tips are designed for single patient use and sterilized between each treatment by using a standard steam autoclave.

The clinical trial results are summarized in Table 8. In this table, “NA” means not available.

TABLE 8 Treatment of Actinic Keratosis. Electrode Screening Visit Subject Length Actinic keratosis Diam. Height Volume Example ID (mm) Date location (mm) (mm) (mm³) 78 01-301 2.00 Sep. 26, 2011 Back of left hand 5.00 0.10 1.23 79 01-302 2.00 Sep. 27, 2011 Back of left hand 8.00 0.10 3.14 80 01-303 2.00 Sep. 26, 2011 Back of right hand 10.00 0.10 4.91 81 01-304 2.00 Oct. 19, 2011 Back of right hand 10.00 0.10 4.91 82 01-305 2.00 Oct. 18, 2011 Left forearm 6.00 0.10 1.77 83 01-306 2.00 Oct. 19, 2011 Back of right hand 10.00 0.10 4.91 84 01-307 4.00 Nov. 14, 2011 Left arm 10.00 0.10 4.91 85 01-308 2.00 Nov. 28, 2011 Right hand 12.00 0.10 7.07 86 01-309 5.00 Dec. 9, 2011 Left forearm 9.00 0.10 3.98 87 02-301 2.00 Oct. 20, 2011 Scalp 4.00 0.10 0.79 Treatment 1 Number of Electrical Energy Applications Applied per per Actinic Actinic Keratosis Keratosis Volume Example Date (#) (mj/mm³) 78 Sep. 27, 2011 7 5366 79 Sep. 29, 2011 10 2995 80 Sep. 29, 2011 8 1533 81 Oct. 27, 2011 20 3833 82 Nov. 7, 2011 8 4259 83 Nov. 8, 2011 5 958 84 Nov. 28, 2011 5 479 85 Dec. 5, 2011 4 532 86 Dec. 16, 2011 5 473 87 Oct. 20, 2011 13 15572 Day 30 Evaluation Diam. Height Volume Growth/Shrink Example Date (mm) (mm) (mm³) (%) 78 Oct. 24, 2011 0.00 0.00 0.00 −100 79 Oct. 25, 2011 7.00 0.10 2.41 −23 80 Oct. 25, 2011 3.00 0.10 0.44 −91 81 Nov. 23, 2011 11.00 0.10 5.94 21 82 Dec. 7, 2011 7.00 0.10 2.41 36 83 Dec. 9, 2011 7.00 0.10 2.41 −51 84 Jan. 3, 2012 11.00 0.10 5.94 21 85 Jan. 6, 2012 8.00 0.00 0.00 −100 86 Jan. 9, 2012 12.00 0.00 0.00 −100 87 Nov. 17, 2011 NA NA NA NA Day 60 Evaluation Duration form Day 30 Diam. Height Volume Growth/Shrink Evaluation Example Date (mm) (mm) (mm³) (%) (Days) 78 Nov. 18, 2011 6.00 0.10 1.77 44 25 79 Nov. 28, 2011 7.00 0.10 2.41 −23 34 80 Nov. 22, 2011 8.00 0.10 3.14 −36 28 81 Dec. 27, 2011 12.00 0.10 7.07 44 34 82 Jan. 5, 2012 5.00 0.10 1.23 −31 29 83 Jan. 6, 2012 7.00 0.10 2.41 −51 28 84 Jan. 27, 2012 0.00 0.00 0.00 −100 24 85 Feb. 3, 2012 4.00 0.00 0.00 −100 28 86 Feb. 13, 2012 12.00 0.00 0.00 −100 35 87 Dec. 15, 2011 0.00 0.00 0.00 −100 28 Day 90 Evaluation Duration form Day Growth/ 30 Diam. Height Volume Shrink. Evaluation Ex. Date (mm) (mm) (mm³) (%) (Days) Concln. 78 Jan. 6, 2012 0.00 0.00 0.00 −100 74 Cleared 79 Jan. 3, 2012 0.00 0.00 0.00 −100 70 Cleared 80 Jan. 10, 2012 0.00 0.00 0.00 −100 77 Cleared 81 Jan. 24, 2012 13.00 0.10 8.30 69 62 Growth 82 Feb. 2, 2012 0.00 0.00 0.00 −100 57 Cleared 83 Feb. 3, 2012 7.00 0.10 2.41 −51 56 Substantial shrinkage 84 Feb. 14, 2012 0.00 0.00 0.00 −100 42 Cleared 85 Mar. 6, 2012 5.00 0.10 1.23 −83 60 Substantial shrinkage 86 Mar. 12, 2012 7.00 0.10 2.41 −40 63 Shrinkage 87 Jan. 11, 2012 0.00 0.00 0.00 −100 55 Cleared

Actinic keratoses were treated in one session (“Treatment 1”).

When an actinic keratosis shrunk to a negligible size (i.e. about 100% shrinkage), it was concluded that the actinic keratosis was “cleared”. In examples where the actinic keratosis shrinkage was in the range of >10% and <50%, it was concluded that there was “shrinkage”. In examples where the actinic keratosis shrinkage was in the range of >50% and <100%, it was concluded that there was “substantial shrinkage”. If the actinic keratosis growth was in the range of >10% to <100%, it was concluded that there was “growth”.

In Examples 78 to 87, nine out of 10 actinic keratoses shrunk (i.e. 90% of cases) after the single treatment session, as observed at “Day 90 Evaluation”. The actinic keratoses were cleared for 6 out of these 10 actinic keratoses (i.e. clearance for at least 60% of the cases). When the application energy was at least 237 mJ/mm³, the actinic keratosis growth was at least prevented for at least 90% of cases. And when the application energy was at least 473 mJ/mm³, the shrinkage was at least 40% for at least 90% of the actinic keratoses cases treated, at least 51% for at least 80% of the cases treated, and at least 83% for at least 60% of the cases treated. These results indicated that single electrical nanopulse treatment session may prevent growth or induce shrinkage of the actinic keratoses for at least 90% of cases. These results further indicated that single electrical nanopulse treatment may clear the actinic keratoses for at least 60% of cases.

In Example 83, the shrinkage of the lesion was about 51% at “Day 30 Evaluation”, about 51% at “Day 60 Evaluation”, and about 51% at “Day 90 Evaluation”. These results indicated that one treatment session may at least prevent the growth of the lesion, or induce at least shrinkage of the lesion or induce at least substantial shrinkage of the lesion, which may last at least 56 days.

Sun radiation particularly, its ultra-violet component, may induce damage to the skin, resulting in aged skin, wrinkled skin, or other sun damaged conditions including actinic keratoses. Since above results indicated that the nanopulse electrical energy treatment may at least prevent growth of actinic keratoses, this treatment may also be used to treat other skin conditions caused by sun radiation.

The components, steps, features, objects, benefits and advantages which have been discussed are merely illustrative. None of them, nor the discussions relating to them, are intended to limit the scope of protection in any way. Numerous other embodiments are also contemplated. These include embodiments which have fewer, additional, and/or different components, steps, features, objects, benefits and advantages. These also include embodiments in which the components and/or steps are arranged and/or ordered differently.

Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications which are set forth in this specification, including in the claims which follow, are approximate, not exact. They are intended to have a reasonable range which is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

All articles, patents, patent applications, and other publications which have been cited in this disclosure are hereby incorporated herein by reference.

Nothing which has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is recited in the claims. 

1. A method of in vivo treatment of a skin lesion, the method comprising: selecting, based on a type of the skin lesion, a duration of an electrical pulse at a full-width-half-maximum and an amplitude of the electrical pulse, wherein the duration is at least 0.01 nanoseconds; determining at least one of a volume of the skin lesion or a surface area of the skin lesion; selecting, based on at least one of the volume of the skin lesion or the surface area of the skin lesion, a configuration of electrodes of a pulse delivery device; determining, prior to a start of a delivery of the electrical energy and based on the duration and the amplitude of the electrical pulse and on the configuration of the electrodes, a total number of electrical pulses to generate for a delivery of electrical energy per volume of the skin lesion of at least 10 mJ/mm³; setting, prior to the start of the delivery of the electrical energy, the duration, amplitude and the total number on a pulse generator connected to the pulse delivery device; and causing the delivery of the electrical energy of at least 10 mJ/mm³ to the skin lesion through the electrodes of the pulse delivery device.
 2. The method of claim 1, wherein the skin lesion comprises malignancies, precancerous lesions, human papilloma virus (HPV) infected cells, immune-related conditions, seborrheic keratosis, acrocordon, aged skin, wrinkled skin, damaged skin, or combinations thereof.
 3. The method of claim 1, wherein the skin lesion comprises basal cell carcinoma, squamous cell carcinoma, actinic keratosis, warts, or combinations thereof.
 4. The method of claim 1, wherein the skin lesion comprises common warts, actinic keratosis, or combinations thereof.
 5. The method of claim 1, wherein the skin lesion comprises common warts, and wherein the electrical energy per volume of the skin lesion is at least 920 mJ/mm³.
 6. The method of claim 1, wherein the skin lesion comprises actinic keratosis, and wherein the electrical energy per volume of the skin lesion is at least 473 mJ/mm³.
 7. The method of claim 1, wherein the pulse duration at the full-width-half-maximum is in the range of 1 nanoseconds to 100 nanoseconds.
 8. The method of claim 1, wherein the pulse duration at the full-width-half-maximum is in the range of 1 nanoseconds to 30 nanoseconds.
 9. The method of claim 1, wherein the electrical field formed by each pulse is at least 1 kV/cm at the peak amplitude of the pulse.
 10. The method of claim 1, wherein the electrical field formed by each pulse is at least 10 kV/cm at the peak amplitude of the pulse.
 11. The method of claim 1, wherein the electrical field formed by each pulse is in the range of 1 kV/cm to 1,000 kV/cm at the peak amplitude of the pulse.
 12. The method of claim 1, wherein the electrical field formed by each pulse is in the range of 10 kV/cm to 100 kV/cm at the peak amplitude of the pulse.
 13. The method of claim 1, wherein the delivery of the electrical energy comprises at least 10 pulses.
 14. The method of claim 1, wherein the delivery of the electrical energy comprises at least 100 pulses.
 15. The method of claim 1, wherein the delivery of the electrical energy comprises at least 1,000 pulses. 16-18. (canceled)
 19. The method of claim 1, wherein the applied electrical energy per volume of the skin lesion is in the range of 10 mJ/mm³ to 10,000 mJ/mm³.
 20. The method of claim 5, wherein the applied electrical energy per volume of the skin lesion is at least 920 mJ/mm³ for at least to prevent growth of the warts.
 21. The method of claim 20, wherein the treatment induces at least 21% shrinkage of the warts. 22-25. (canceled)
 26. The method of claim 6, wherein the applied electrical energy per volume of the skin lesion is at least 473 mJ/mm³ to at least prevent growth of the actinic keratosis.
 27. The method of claim 26, wherein the treatment induces at least 20% shrinkage of the actinic keratosis. 28-34. (canceled) 